Smoke-Producing Compositions

ABSTRACT

The present disclosure relates to non-toxic smoke-producing compositions for producing colored smoke. In particular, the smoke-producing compositions are free from chlorinated compounds and organic dyes from the family of anthraquinones (or derivatives). The smoke-producing compositions can be used to produce pyrotechnic devices suitable for use in the military and civilian fields.

FIELD OF THE INVENTION

The present invention relates to non-toxic smoke-producing compositionsfor producing colored smoke. In particular, the smoke-producingcompositions are free from chlorinated compounds and organic dyes fromthe family of anthraquinone (or derivatives). The smoke-producingcompositions can be used to prepare pyrotechnic devices suitable for usein the military and civilian field.

TECHNOLOGICAL BACKGROUND

Smoke-producing compositions for producing colored smoke generallycomprise an oxidizing/reducing couple and an organic dye in powder form.The production of colored smoke from such compositions is based on aprinciple of sublimation. During the combustion of theoxidizing/reducing couple, the heat generated by the combustion causesthe organic dye to change from the solid state to the gaseous state.Colored smokes are generated when the organic dye condenses in theatmosphere.

A large number of the organic dyes used in smoke-producing compositionsare dyes from the family of anthraquinone (or derivatives) (polycyclicaromatic hydrocarbons, PAHs) which allow the generation of yellow, red,blue or green smokes. Some of these derivatives have or may have a riskto the environment or human health. Moreover, when the compositionscomprise organic dyes whose decomposition temperature is less than thecombustion temperature of the oxidizing/reducing couple, the dye can bedestroyed and generate more or less toxic combustion entities. Incompositions containing potassium chlorate as a reducing agent, theseentities can be associated with chlorine atoms and possibly formmolecules of the dioxin type. Dioxins, like polycyclic aromatichydrocarbons, are classified as persistent organic pollutants (POPs). Inorder to protect human health and the environment against POPs,manufacturers aim at reducing their unintentional production.

However, the production of smoke-producing compositions that do not havea risk to the environment or to human health remains a challenge. Thus,the simple substitution of a component, the use of which may becontroversial, by a component that does not have the aforementioneddisadvantages does not prove to be easy given the number of requirementswhich the components of such compositions must meet in order to allowthe production and marketing of high-performance smoke-producingcompositions. Thus, the smoke-producing compositions for producingcolored smoke must be stable over time and withstand climaticvariations, in particular high temperature variations. They must have anacceptable burn time and smoke efficiency. In addition to non-toxicityfor humans, they must also meet a large number of environmentalrequirements (non-toxicity, compliance with REACH regulations,limitation of non-biodegradable inert waste from firing).

Thus, a need remains for the provision of high-performance non-toxicsmoke-producing compositions which allow to meet the above requirementsand which do not contain organic dyes liable to generate POPs, inparticular which do not contain organic dyes from the family ofanthraquinone (or derivatives) and which are free from chlorinatedcompounds.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a smoke-producing compositioncomprising, relative to the total weight of the composition:

-   -   from 24 to 52% by weight of potassium nitrate as oxidant;    -   from 15 to 40% by weight of a reducing agent selected from the        group consisting of dextrose, lactose, sucrose, dextrin, starch        and mixtures thereof;    -   from 6 to 60% by weight of a non-salified sublimable organic dye        in powder form;        wherein the sublimable organic dye:    -   has a sublimation temperature of less than 450° C., the        sublimation temperature being less than the decomposition        temperature of the sublimable organic dye;    -   has a decomposition temperature higher than the combustion        temperature of the smoke-producing composition; and    -   the sublimable organic dye is selected from the group consisting        of dyes from the family of thioxanthenes, nitrobenzamines,        perylenes, benzimidozoles, naphthols, terephthalates,        phthalocyanines, violanthrones, xanthenes, azobenzenes,        pyrazolinones, the dyes Pigment Blue 66, Solvent Blue 2, Solvent        Red 179 and mixtures thereof.

The present invention also relates to a pyrotechnic device comprisingsuch a smoke-producing composition as well as to its use for civil ormilitary use.

Other aspects of the invention are as described below and in the claims.

DETAILED DESCRIPTION OF THE INVENTION

The research carried out by the inventors has allowed to developsmoke-producing compositions that meet the need expressed.

The smoke-producing compositions of the present invention comprise

-   -   from 24 to 52% by weight, relative to the total weight of the        composition, of potassium nitrate (KNO₃) as oxidant;    -   from 15 to 40% by weight, relative to the total weight of the        composition, of a reducing agent selected from the group        consisting of dextrose, lactose, sucrose, dextrin, starch and        mixtures thereof;    -   from 6 to 60% by weight, relative to the total weight of the        composition, of a non-salified sublimable organic dye in powder        form;        wherein:    -   the sublimable organic dye has a sublimation temperature less        than 450° C., the sublimation temperature being less than its        decomposition temperature;    -   the sublimable organic dye has a decomposition temperature        higher than the combustion temperature of the smoke-producing        composition; and    -   the sublimable organic dye is selected from the group consisting        of dyes from the family of thioxanthenes, nitrobenzamines,        perylenes, benzimidozoles, naphthols, terephthalates,        phthalocyanines, violanthrones, xanthenes, azobenzenes,        pyrazolinones, the dyes Pigment Blue 66, Solvent Blue 2, Solvent        Red 179 and mixtures thereof.

Such smoke-producing compositions have good technical performance: suchas good combustion efficiency, good smoke density and pure color. Thus,the smoke-producing compositions of the present invention offer a verygood combustion efficiency. Thus, combustion efficiencies above 45% areconsidered good and above 60% are considered very good. Suchefficiencies allow the colored smoke to be visible over 5 km away incalm weather. The smoke density is greater than 5 g/cm³. Thus, thecompositions of the present invention allow to obtain excellent smokedensities (greater than 5 g/cm³). The color of the smokes ischaracterized by measuring the colorimetry (Cylab coordinates) just forinformation.

Moreover, the smoke-producing compositions of the present invention areadvantageously free from components listed to date in Annexes XIV andXVII of the REACH regulations and do not belong to the raw materialsclassified as toxic (bearing the mentions H314, H318, H300, H310, H311,H330, H331, H370, H372, H334, H350, H340, H360, H410 and H420). Theabsence of such components, in particular of toxic dyes, limits therisks for users exposed in the shorter or longer term to the smokesgenerated. Thus, the use of the compositions of the present inventiondoes not have any known risks for human health and the environment.

The absence of dyes from the family of anthraquinone (or derivatives)and the absence of chlorine in the formulation of the smoke-producingcompositions of the present invention allows to limit the production ofharmful entities during their combustion and the production ofnon-biodegradable inert waste.

Advantageously, the smoke-producing compositions of the presentinvention do not comprise chlorinated components. The combustionentities generated therefore do not comprise chlorinated compounds, forexample in the form of dioxins.

In the present description, unless explicitly stated otherwise, the term“a” designates one or more.

The smoke-producing compositions of the present invention comprise from24 to 52% by weight, relative to the total weight of the composition, ofpotassium nitrate (KNO₃) as oxidant. In some embodiments, thesmoke-producing compositions comprise from 26 to 48% by weight ofpotassium nitrate.

The smoke-producing compositions of the present invention comprise from15 to 40%, or from 18 to 35% by weight, relative to the total weight ofthe composition, of a reducing agent selected from the group consistingof dextrose, lactose, sucrose, dextrin, starch and mixtures thereof. Insome embodiments, the smoke-producing compositions comprise from 18 to35% by weight of a mixture of reducers. In some embodiments, thereducing agent is sucrose or starch.

The smoke-producing compositions of the present invention comprise from6 to 60% by weight, relative to the total weight of the composition, ofa non-salified sublimable organic dye in powder form. In someembodiments, the smoke-producing compositions comprise from 10 to 45% byweight of a non-salified sublimable organic dye in powder form.

The term “sublimable organic dye” refers to the ability of a dye totransition directly from the solid state to the gaseous state.

The term “non-salified” indicates that the organic dye is not in theform of a salt, such as a dye in monosodium or disodium form.

The sublimable organic dyes suitable for use in the context of thepresent invention must have a decomposition temperature higher than thecombustion temperature of the smoke-producing composition. Theirdecomposition temperature must also be higher than their sublimationtemperature.

The combustion temperatures of the smoke-producing compositions of thepresent invention vary according to the oxidizing/reducing coupleselected. Thus, the combustion temperatures of the smoke-producingcompositions may be as follows:

-   -   about 300° C. for the potassium nitrate/sucrose couple;    -   about 350° C. for the potassium nitrate/starch couple;    -   about 450° C. for the potassium nitrate/lactose couple.

Organic dyes therefore have a decomposition temperature higher than 300°C. or higher than 350° C. or higher than 450° C.

The sublimable organic dye comes in the form of a powder. Preferably,the particles making up the powder are not nanoparticles, they do nothave a nanometric size (1 to 100 nm). The absence of nanoparticleorganic dyes limits the health risks for users exposed to the smokesgenerated. Preferably, the size of the particles does not exceed 200 μm.Such particles provide better dispersion in the smoke cloud.

Thus, preferably, the sublimable organic dye is in the form of a powderwhose particles have a size greater than 1 μm, generally a size varyingfrom 6 to 200 μm as measured by counting under a microscope (zoom ×84).It is understood that, within this range, the average particle size mayvary depending on the organic dye selected.

The examples of specific dyes useful in the present invention arereferred to by their generic name as referenced in the “Color IndexInternational” database (2020).

An example of dyes from the thioxanthene family, suitable for use in thecontext of the present invention includes the dye Solvent Yellow 98.

Examples of dyes from the nitrobenzamine family, suitable for use in thecontext of the present invention include the dyes Pigment Yellow 65 andPigment Green 8.

An example of dyes from the perylene family, suitable for use in thecontext of the present invention includes the dye Solvent Green 5.

Examples of dyes from the benzimidazole family, suitable for use in thecontext of the present invention include the dyes Solvent Red 196 andPigment Red 194.

Examples of dyes from the naphthol family, suitable for use in thecontext of the present invention include the dyes Solvent Yellow 14,Solvent Red 24, Solvent Red 25, Solvent Red 26, Solvent Red 27, PigmentRed 1, Solvent Red 164, Solvent Yellow 56 and Pigment Red 170.

Examples of dyes from the terephthalate family, suitable for use in thecontext of the present invention include the dyes Solvent Yellow 155 andPigment Yellow 175.

Examples of dyes from the phthalocyanine family, suitable for use in thecontext of the present invention include the dyes Solvent Blue 70 andSolvent Blue 67.

Examples of dyes from the violanthrone family, suitable for use in thecontext of the present invention include the dyes Vat blue 20, Vat green1, Vat blue 16 and Vat green 2 (also called Pigment Green 54).

An example of a dye from the xanthene family, suitable for use in thecontext of the present invention includes the dye Solvent Green 4.

Examples of dyes from the pyrazolinone family, suitable for use in thecontext of the present invention include Vat Blue 5, Solvent Yellow 16,Pigment Yellow 154, Pigment Yellow 175 and Solvent Yellow 93.

Examples of dyes from the azobenzene family, suitable for use in thecontext of the present invention include Solvent Yellow 14, Solvent Red24, Solvent Red 25, Solvent Red 26, Solvent Red 27, Pigment Red 1,Solvent Yellow 56 and Solvent Red 164.

Thus, in some embodiments, the non-salified sublimable organic dye isselected from the group consisting of Solvent Green 4, Pigment Yellow65, Pigment Green 8, Solvent Green 5, Solvent Red 196, Pigment Red 194,Solvent Yellow 14, Solvent Red 24, Solvent Red 25, Solvent Red 26,Solvent Red 27, Pigment Red 1, Solvent Yellow 56, Solvent Red 164,Pigment Red 170, Solvent Yellow 155, Pigment Yellow 175, Solvent Yellow98, Solvent Blue 70, Solvent Blue 67, Vat Blue 20, Vat Green 1, VatGreen 2, Vat Blue 16, Vat Blue 5, Solvent Yellow 16, Pigment Yellow 154,Pigment Yellow 175, Solvent Yellow 93, Pigment Blue 66, Solvent Blue 2,Solvent Red 179 and mixtures thereof.

In some embodiments, the organic dye is selected from the groupconsisting of Solvent green 5, Pigment Red 194, Solvent Red 24, SolventRed 25, Solvent Red 26, Solvent Red 27, Solvent Yellow 56, SolventYellow 14, Vat Green 2, Solvent Yellow 98, Solvent Yellow 16, SolventYellow 93, Pigment Blue 66, Solvent Red 179 and mixtures thereof. Suchorganic dyes have a decomposition temperature higher than the combustiontemperature of the smoke-producing composition and higher than theirsublimation temperature. Such organic dyes do not have toxicity. Thus,the smoke-producing compositions comprising such dyes do not represent adanger for humans exposed in the shorter or longer term to the generatedsmokes.

The smoke-producing compositions of the present invention may furthercomprise additives commonly employed in the technical field, such asbinders, phlegmatizers, moisture absorbers, combustion regulators, flameinhibitors and mixtures thereof.

In some embodiments, the smoke-producing compositions comprise from 0.5to 10%, preferably from 5 to 10%, by weight relative to the total weightof the composition, of a phlegmatizer and/or from 0.5 to 8%, preferablyfrom 1 to 3%, relative to the total weight of the composition, of abinder and/or from 0.5 to 10% by weight, preferably from 5 to 10%,relative to the total weight of the composition, of a flame inhibitor.

The smoke-producing compositions of the present invention may comprisefrom 1 to 18% by weight of optional additives relative to the totalweight of the composition. The sum of the percentages by weight ofoxidant, reducer, organic dye and optional additives is then equal to100%.

Examples of binders suitable for use in the context of the presentinvention include gum arabic, epoxy resin, shellac and polyethylene wax.

Examples of phlegmatizers suitable for use in the context of the presentinvention include talc, kaolin (white clay made from aluminum silicate),kieselguhr, micronized silica and realgar.

Examples of combustion regulators suitable for use within the context ofthe present invention include hydrated alumina, paranitraniline,graphite and auramine N65.

Examples of flame inhibitor suitable for use in the context of thepresent invention include sodium hydrogencarbonate and calciumcarbonate.

The person skilled in the art, on the basis of his technical knowledge,will be able to select the components and proportions of the componentsof the composition in order, for example, to reconcile chemicalcompatibility, volume ratio between pyrotechnic composition (oxidant,reducer and additives) and dyes (depending on the density of the dyes)and/or combustion rate. In particular, the person skilled in the artwill be able to select the reducer/oxidant/dye combination deliveringthe best performance.

In some embodiments, the dye Solvent Yellow 93 will preferably be usedin combination with starch as a reducing agent.

In some embodiments, the smoke-producing compositions of the presentinvention comprise:

-   -   from 24 to 52%, preferably from 26 to 48% by weight, relative to        the total weight of the composition, of an oxidant (potassium        nitrate);    -   from 15 to 40%, preferably from 18 to 35% by weight, relative to        the total weight of the composition, of one or more reducer(s)        selected from the group consisting of dextrose, lactose,        sucrose, dextrin and starch;    -   from 6 to 60%, preferably from 10 to 45% by weight, relative to        the total weight of the composition, of a non-salified        sublimable organic dye in powder form;    -   optionally from 1 to 18% by weight, relative to the total weight        of the composition, of additives, typically selected from the        group consisting of binders, phlegmatizers, flame inhibitors,        moisture absorbers, combustion regulators and mixtures thereof.

The proportions of oxidant, reducer, organic dye and additives arechosen so that the sum of the percentages is equal to 100%.

In some embodiments, the smoke-producing compositions of the presentinvention comprise:

-   -   from 24 to 52%, preferably from 26 to 48% by weight, relative to        the total weight of the composition, of potassium nitrate        (KNO₃);    -   from 15 to 40%, preferably from 18 to 35% by weight, relative to        the total weight of the composition, of one or more reducing        agent(s) selected from the group consisting of lactose, sucrose        and starch;    -   from 6 to 60%, preferably from 10 to 45% by weight, relative to        the total weight of the composition, of a non-salified        sublimable organic dye in powder form;    -   from 0.5 to 10%, preferably from 5 to 10%, by weight relative to        the total weight of the composition, of a flame inhibitor;    -   from 0.5 to 8%, preferably from 1 to 2%, relative to the total        weight of the composition, of a binder;        the sum of the percentages by weight of oxidant, reducer,        organic dye, flame inhibitor and binder being equal to 100%.

In these embodiments, the sublimable organic dye can be as describedabove.

The smoke-producing compositions of the present invention can beproduced according to methods well known to the person skilled in theart. Thus, the method described in the “Examples” section can easily betransposed on a large scale.

The smoke-producing compositions of the present invention can be used toproduce pyrotechnic devices generating colored smoke, such as coloredsmoke grenades, signaling smokes (for example SNCF signals), trainingsmokes, etc.

Thus, the present invention also relates to pyrotechnic devicescomprising a smoke-producing composition according to the presentinvention.

The smokes generated can be yellow, red, blue or green depending on theuse and the needs.

Pyrotechnic devices can be used in the civilian (for example paintball,demonstration, football match, . . . ) or military field.

They can allow to make position marking, to alert or to inform accordingto the color of the smoke.

The following examples are given for illustrative purposes, but shouldin no way be considered as limiting the present invention.

EXAMPLES Methods

The technical performance of the smoke-producing compositions, such asthe density of the smoke, the duration of combustion, the combustionefficiency and the intensity of the color of the smoke are evaluated atroom temperature (20-25° C.) in an experimental device comprising:

-   -   a 0.635 m³ box fitted with a filter disposed at the smoke        outlet;    -   a visible camera allowing to measure the combustion time;    -   a thermocouple allowing to measure the combustion temperature.

The produced models are weighed before and after combustion, thusallowing to determine the mass of the composition before combustion(mass_(composition before combustion)) and the mass of the compositionafter combustion (mass_(combustion residue)).

Smoke Density

The smoke density (d), expressed in grams per cubic centimeter, isdetermined by the following relationship:

$d = \frac{{mass}_{{composition}{before}{combustion}} - {mass}_{{combustion}{residue}}}{{Volume}_{box}\left( {{0.6}35m^{3}} \right)}$

Combustion Time

The combustion time is measured by means of the camera.

Combustion Efficiency

The combustion efficiency, expressed as a percentage, is determined bythe following relationship:

$r = \frac{{mass}_{{composition}{before}{combustion}} - {mass}_{{combustion}{residue}}}{{mass}_{{composition}{after}{combustion}}}$

Colorimetry

Colorimetry allows to characterize a color by numerical values L*a*b*(CIELAB). L*a*b* color space (CIELAB) is a system adopted by theInternational Commission on Illumination in 1976.

L* a* b* are measured in the space

-   -   L*: saturation    -   a*: red/green component    -   b*: blue/yellow component

The evolution or color difference (DE) can be followed by therelationship:

DE=[(DL*)²+(Da*)²+(db*)²]^(1/2)

where DL*, Da*, db* are the color difference values between the sampleand the reference.

The color intensity is measured by a colorimeter disposed directly onthe fume recovery filter (sublimated dye deposition on the filter).

Examples of Production of Smoke-Producing Compositions

The smoke-producing compositions were produced from the following rawmaterials:

-   -   Potassium nitrate, CAS Nº: 7757-79-1;    -   Lactose, CAS Nº: 63-42-3;    -   Sucrose, CAS Nº: 57-50-1;    -   Starch, CAS Nº: 9005-25-8;    -   Gum arabic (gum), CAS Nº: 9000-01-5;    -   Sodium hydrogen carbonate (NaHCO₃), CAS Nº: 144-55-8;    -   Sublimable organic dyes:        -   Solvent Yellow 98 (SY98), CAS Nº: 27870-92-4;        -   Solvent Yellow 56 (SY56), CAS Nº: 2481-94-9;        -   Solvent Red 24 (SR24), CAS Nº: 85-83-6;        -   Pigment Red 1 79 (PR196), CAS Nº: 6829-22-7;        -   Pigment Blue 66 (PB66), CAS Nº: 482-89-3;        -   Solvent Green 5 (SG5), CAS Nº: 79869-59-3.

The formulations of the smoke-producing compositions produced are aspresented in Table 1. The percentages indicated are percentages byweight expressed relative to the total weight of the smoke-producingcomposition.

TABLE 1 Formulations of smoke-producing compositions CF1 CF2 CF3 CF4 CF5CF6 Potassium  33%  35% 36.5%  46% 34.3% 42.4%  nitrate Lactose 17.6% XX 24.5%  X X Sucrose  4.4% X X 6.1% 22.9 X Starch X 24.2 21.9 X X 25.4NaHCO₃   4%   3%   3% 5.5% 4.2% 3.4% Gum  1.6%  1.6%  1.6% 2.2% 1.6%1.8% Dye SY98 SY56 SR24 SR179 PB66/SY98 SG5 39.4% 36.2%  37% 15.7% 22.5%/  27%

The smoke-producing compositions were produced according to the detailedprotocol presented below.

Production of Raw Materials

-   -   A gummed water solution was produced at 7.5% in demineralized        water.    -   The oxidant and the reducers were baked at 50° C.-48 hours        before mixing.    -   The oxidant and the reducers were stored in sealed jars, at 30°        C.+/−5° C.    -   The oxidant and the reducers were crumbled at 500 μm,    -   Crumbling the flame inhibitor (NaHCO₃) at 500 μm,

Production of Smoke-Producing Compositions

-   -   The dye, the reducers and the flame inhibitor were weighed into        the mixing vessel.    -   They were mixed until a homogeneous color powder was obtained.    -   The binder was introduced into the preparation, then mixed until        a homogeneous color powder was obtained.    -   The oxidant was in turn introduced to the mixture and it was        mixed until a homogeneous color powder was obtained.

Fractionation/Granulation

-   -   The mixture was poured into a large 630 μm sieve, then the        composition was granulated manually on the 630 μm sieve. The        composition under the sieve was retained.

Drying:

-   -   The composition was placed in a ventilated oven at 40° C. for a        minimum of 2 days.

Grinding/Storage:

-   -   The composition was sifted through a 200 μm sieve, then it was        stored in sealed and well-identified 200 g bags.

Production of Models

-   -   In a bakelite hoop, 5 g of PTFE was introduced (to be used as a        background).    -   The height H1 was measured. It corresponds to the height        available in the hoop.    -   5 g of the smoke-producing composition were introduced into the        hoop as well as 0.5 g of BNP (ignition composition).    -   The whole was compressed to a pressure of 500 Kg.    -   The height H2 was measured. It corresponds to the height        available in the fret.    -   The height of the composition H3 was calculated according to the        following formula: H3 ═H1-H2.    -   The hoop was then disposed in a metal case allowing        pressurization.

Performance Evaluation of Smoke-Producing Compositions

The performance of the smoke-producing compositions was evaluatedaccording to the methods described above. The results are shown in Table2.

TABLE 2 Performance of smoke-producing compositions Combustionefficiency Smoke density (%) (g/cm³) CF1 7.1 74.7 CF2 6.8 70.3 CF3 7.378.9 CF4 8.1 81.4 CF5 7.3 74.3 CF6 6.8 79.2

The smoke-producing compositions of the present invention are non-toxicand effective.

1. A smoke-producing composition comprising, relative to the totalweight of the composition: from 24 to 52% by weight of potassium nitrateas oxidant; from 15 to 40% by weight of a reducing agent selected fromthe group consisting of dextrose, lactose, sucrose, dextrin, starch andmixtures thereof; from 6 to 60% by weight of a non-salified sublimableorganic dye in powder form; wherein the sublimable organic dye: has asublimation temperature of less than 450° C., the sublimationtemperature being less than the decomposition temperature of thesublimable organic dye; has a decomposition temperature higher than thecombustion temperature of the smoke-producing composition; and thesublimable organic dye is selected from the group consisting of dyesfrom the family of thioxanthenes, nitrobenzamines, perylenes,benzimidozoles, naphthols, terephthalates, phthalocyanines,violanthrones, xanthenes, azobenzenes, pyrazolinones, the dyes PigmentBlue 66, Solvent Blue 2, Solvent Red 179 and mixtures thereof.
 2. Thesmoke-producing composition according to claim 1, wherein the sublimableorganic dye is selected from the group consisting of Solvent Green 4,Pigment Yellow 65, Pigment Green 8, Solvent Green 5, Solvent Red 196,Pigment Red 194, Solvent Yellow 14, Solvent Red 24, Solvent Red 25,Solvent Red 26, Solvent Red 27, Pigment Red 1, Solvent Yellow 56,Solvent Red 164, Pigment Red 170, Solvent Yellow 155, Pigment Yellow175, Solvent Yellow 98, Solvent Blue 70, Solvent Blue 67, Vat Blue 20,Vat Green 1, Vat Green 2, Vat Blue 16, Vat Blue 5, Solvent Yellow 16,Pigment Yellow 154, Pigment Yellow 175, Solvent Yellow 93, Pigment Blue66, Solvent Blue 2, Solvent Red 179 and mixtures thereof.
 3. Thesmoke-producing composition according to claim 1, wherein the sublimableorganic dye is selected from the group consisting of Solvent green 5,Pigment Red 194, Solvent Red 24, Solvent Red 25, Solvent Red 26, SolventRed 27, Solvent Yellow 56, Solvent Yellow 14, Vat Green 2, SolventYellow 98, Solvent Yellow 16, Solvent Yellow 93, Pigment Blue 66,Solvent Red 179 and mixtures thereof.
 4. The smoke-producing compositionaccording to claim 1 further comprising additives selected from thegroup consisting of binders, phlegmatizers, moisture absorbers,combustion regulators, flame inhibitors and mixtures thereof.
 5. Thesmoke-producing composition according to claim 1 further comprising from0.5 to 8% by weight, relative to the total weight of the composition, ofa binder.
 6. The smoke-producing composition according to claim 1further comprising from 0.5 to 10% by weight, relative to the totalweight of the composition, of a flame inhibitor.
 7. The smoke-producingcomposition according to claim 1, wherein the sublimable organic dye isa powder whose particle size does not exceed 200 μm.
 8. Thesmoke-producing composition according to claim 1, wherein thedecomposition temperature of the dye is higher than 300° C.
 9. Thesmoke-producing composition according to claim 1 comprising: from 26 to48% by weight of the oxidant; from 18 to 35% by weight of the reducer;from 10 to 45% by weight of the sublimable organic dye.
 10. Apyrotechnic device comprising a smoke-producing composition according toclaim
 1. 11. The pyrotechnic device according to claim 10 selected fromsmoke grenades, signaling smoke or training smokes.
 12. Use of apyrotechnic device according to claim 10 for civil or military use.